Update SchumannR Romanzen to 2.18.2
Use StaffGroup instead of PianoStaff to facilitate 3rd "piano" staff
Move explicit breaks to a break voice to allow sizing distance between the first staff pair.
GloverCW/thinkhome: Convert to 2.18
CareyH/sally: Convert to 2.18
AdamsS/bluemtns: Convert to 2.18
AbtF/swallows: Convert to 2.18
convert-ly
Formatting and spacing  edits for 2.18.2
Automated re-indentation
Spacing fix and a few more adjustments
set MIDI melody to choir aahs
DevienneF/O70: fix suboptimal line break

On the A4 rendering, a linebreak was occurring immediately after the anacrusis. Added a \noBreak to the following bar to prevent this.
Merge branch 'GloverCW' of https://github.com/doughdemon/The-Mutopia-Project
Header tweaks
Merge branch 'AbtF' of https://github.com/doughdemon/The-Mutopia-Project
Header tweaks
Merge branch 'AdamsS' of https://github.com/doughdemon/The-Mutopia-Project
Header tweaks
Merge branch 'CareyH' of https://github.com/doughdemon/The-Mutopia-Project
Header tweaks
Merge branch 'fishers' of https://github.com/PaulMorris/The-Mutopia-Project